package com.剑指offer.no10;

public class Solution {
    public int numWays(int n) {
        // ---------------初始情况-------------
        if(n <= 1){
            return 1;
        }
        if(n == 2){
            return 2;
        }

        // ---------------初始化dp数组-------------
        int[] dp = new int[n+1];

        dp[0] = 1;
        dp[1] = 1;
        dp[2] = 2;

        // -------------状态转移过程-----------------------
        for(int i =3; i<=n; i++){

            dp[i] = (dp[i-1] + dp[i-2]) % 1000_000_007;;
        }
        return dp[n];

    }
}
